Daniel Cousens

@karel-3d shall I rebase/merge this?

What are the benefits of this PR?

@karel-3d the data you bring in, probably needs to be attributed/linked back to https://github.com/Xekyo/CoinSelectionSimulator in some way? (@Xekyo)

Did it change in bitcoin core?

Options: * `.witness` field for each `input`, or * `.prevOutScript`/`.prevOutType` for each `input` The latter is probably better...

`.script.length` is used now for estimation [if provided] - without it, [it assumes P2PKH.](https://github.com/bitcoinjs/coinselect/blob/master/utils.js#L8-L14) If you're implementation can pre-sign all inputs, but with fake/blank signatures [for security], then `script.length` and...

> Hm, but pre-signing all inputs with empty/fake privkeys will complicate things and needlessly slow down computation Not necessarily, it should be no different then the approach we'd be taking...

Resolved partially by https://github.com/bitcoinjs/coinselect/pull/22#discussion_r133176608 - but - the virtual size calculation isn't accounted for yet? `.witness` would need to be provided?

Blackjack attempts to hit the target value, but not exceed it by `threshold`. You probably want an accumulative strategy instead.

What do you get if you call (normally) `bip39.generateMnemonic()`?